1. Field of the Invention
The present invention relates generally to refrigerated air conditioning systems, and more particularly, to an apparatus utilizing either solar energy or the differential of wet-bulb and dry-bulb temperatures of ambient air to evaporate a first refrigerant and utilizing the pressure developed by the evaporated first refrigerant for pumping or compressing a second refrigerant circulated within a refrigeration system.
2. Description of the Prior Art
Once abundant sources of energy such as oil and natural gas are now relatively less abundant and more expensive. As a result, utilization of solar energy has attracted much attention in the recent past. For example, it is known to employ solar energy in conjunction with a refrigeration system as disclosed in U.S. Pat. No. 4,023,948 issued to Pitts et al. The patent issued to Pitts et al. discloses a solar energy refrigeration and air conditioning system wherein a plurality of solar collectors are used to heat a fluid, and the heated fluid is circulated through a heat exchanger for vaporizing a refrigerant. The vaporized refrigerant is passed through an ejector which creates a suction for drawing refrigerant vapors from an evaporator into the ejector. The ejector is in turn coupled to a condenser wherein the refrigerant is condensed. A portion of the condensed refrigerant is recirculated to the heat exchanger by a pump. The remainder of the condensed refrigerant is circulated to an evaporator for cooling an enclosed area.
A disadvantage of the apparatus disclosed by Pitts et al. is that the fluid recirculated within the loop between the heat exchanger and the condenser is combined, within the ejector, with the fluid recirculated within the loop between the condenser and the evaporator. Thus, the suction inlet within the ejector disclosed by Pitts et al. may not be utilized for circulating a fluid other than the fluid recirculated between the heat exchanger and the condenser. This limitation precludes, for example, the use of two different refrigerants within the two different recirculation loops.
In U.S. Pat. No. 2,942,411 issued to Hutchings, an apparatus is disclosed which utilizes solar energy to compress a gas, the compressed gas being stored for subsequent utilization by an air motor for generating electricity. In the apparatus disclosed by Hutchings, water is circulated through a solar boiler for creating steam which drives a turbine for turning a gas compressor. The gas compressor is utilized to compress a non-liquified gas such as methane. However, the solar boiler used to create the steam required collectors which optically concentrate the sun rays, such as parabolically shaped mirrored reflectors. Construction of such solar boilers for creating steam from water is complex and expensive.
Moreover, systems which utilize solar energy of the type described in the above mentioned patents are typically operative only during daylight hours and only when the intensity of the sun is relatively strong. Such systems are not actively driven on cloudy days or at night.
U.S. Pat. No. 4,103,493, issued to Schoenfelder, discloses an apparatus utilizing a solar collector for boiling a refrigerant. The boiled refrigerant is conducted to a Rankine cycle engine for generating rotary motion. The rotary motion created by the Rankine cycle engine is transmitted through a gear box to rotate a conventional compressor within a heat pump system. The use of a Rankine cycle engine to create rotary motion may be advantageous in some respects, for example, to drive an electrical generator as shown by Schoenfelder. However, the transformation of the energy contained within the pressurized refrigerant to rotary motion and the subsequent retransformation of such rotary motion to pressurize a gas within a compressor presents some disadvantages. Energy losses due to friction within the gear box and within the compressor of the Schoenfelder apparatus reduce the efficiency of energy transfer from the solar collection circuit to the heat pump system. Moreover, both the physical size and expense of the combination of the Rankine cycle engine, the gear box and the compressor are considerable.
Accordingly, it is an object of the present invention to provide an apparatus for compressing a refrigerant within a refrigeration system, the apparatus utilizing solar energy for vaporizing a driving fluid while maintaining physical isolation between the driving fluid and the refrigerant to be compressed.
Another object of the present invention is to provide an apparatus utilizing solar energy for compressing a refrigerant within a refrigeration system wherein conventional flat solar panels may be used for collecting solar energy, thereby avoiding the complexity and expense of optical concentration-type solar collectors.
It is still another object of the present invention to provide an apparatus for compressing a refrigerant within a refrigeration system, the apparatus being adapted to utilize heat extracted from the surroundings for vaporizing a driving fluid in order to compress the refrigerant.
A further object of the present invention is to provide a refrigeration system which may utilize solar energy for vaporizing a driving fluid wherein the driving fluid may be different from a refrigerant circulated within the refrigeration system.
A yet further object of the present invention is to provide a refrigeration system which can extract heat from the surroundings to vaporize a driving fluid which can be used to recirculate a refrigerant within the refrigeration system.
A still further object of the present invention is to provide a refrigeration system adapted to utilize the temperature differential between wet-bulb and dry-bulb temperatures to create a pressure differential within a first refrigerant circuit, and to utilize the pressure differential thereby produced to compress a second refrigerant within a second refrigerant circuit.
Yet another object of the present invention is to provide a relatively simple, and efficient, and inexpensive refrigerated air conditioning system suitable for refrigerating the air within a home, which refrigeration system substantially reduces the amount of electrical power typically required to cool the home.